Apple GarageBand for iPad

Although it has similarities to the Mac version (and projects started on your tablet can be imported into it) GarageBand for iPad is very much its own app. There are Touch and Smart Instruments, an eight-track sequencer and a decent selection of guitar amps and stompboxes.

What you don't get is anything in the way of MIDI editing, and file import/export options are also limited. But GarageBand for iPad is still a winner: plug in a controller keyboard via the Camera Connection Kit and you've got a powerful, fun and portable song sketching solution.